Chemists crack secrets of nature's super glue

01/07/04

ARLINGTON, Va.-Researchers have discovered that iron in seawater
is the key binding agent in the super-strong glues of the common
blue mussel, Mytilus edulis. This is the first time researchers
have determined that a metal such as iron is critical to forming
an amorphous, biological material.

In addition to using the knowledge to develop safer alternatives
for surgical and household glues, the researchers are looking at
how to combat the glue to prevent damage to shipping vessels and
the accidental transport of invasive species, such as the zebra
mussel that has ravaged the midwestern United States.

National Science Foundation CAREER awardee Jonathan Wilker, Mary
Sever and their colleagues at Purdue University announce their
discovery in the Jan. 12 issue of Angewandte Chemie.

En route to crafting synthetic versions of the glue, the
researchers discovered that bivalves extract the metal iron from
the surrounding seawater and use it to join proteins together,
linking the fibrous molecules into a strong, adhesive mesh. The
800 mussels in Wilker's laboratory have an uncanny ability to
stick to almost anything, even TeflonŽ.

Comment from Wilker regarding research:
"Mussel glues present the first identified case in which
transition metals are essential to the formation of a non
crystalline biological material," says NSF CAREER awardee
Jonathan Wilker of Purdue University.

"We are curious as to whether or not this newly discovered, metal-
mediated protein cross-linking mechanism of material formation is
a prevalent theme in biology. We will be exploring systems such
as barnacle cement, kelp glue and oyster cement to see how other
biomaterials are produced," says NSF CAREER awardee Jonathan
Wilker of Purdue University.

"The biological origin of this glue and the ability to stick to
nearly all surfaces invite applications such as the development
of surgical adhesives," says NSF CAREER awardee Jonathan Wilker
of Purdue University.

"Understanding how marine glues are formed could be key to
developing surfaces and coatings to prevent adhesion processes.
Current antifouling paints rely upon releasing copper into
surrounding waters, thereby killing barnacles in their larval
state. We are hoping our results will help make antifouling
paints that do not require the release of toxins into the marine
environment," says NSF CAREER awardee Jonathan Wilker of Purdue
University.

NSF comments regarding the research discovery and the Wilker
group:
"It appears that the strength, sticking power and endurance of
these extraordinary biological materials may derive from
inorganic chemistry," says chemist Mike Clarke, the NSF program
officer who oversees Wilker's award.

"Proteins often rely on metal ions to tie them together and
provide stability, but this is the first time that a transition
metal ion has been determined to be an integral part of a
biological material," says chemist Mike Clarke, the NSF program
officer who oversees Wilker's award.

"The research wonderfully illustrates the potential for metal
ions to strengthen materials by cross-linking polymer chains.
More important to researchers is the tantalizing suggestion that
the remarkable adhesive properties of these biological glues lie
in an iron-dependent oxidation to radicals," says chemist Mike
Clarke, the NSF program officer who oversees Wilker's award.

"This discovery could lead to the creation of unusual new
materials with designed plasticity, strength and adhesiveness for
household, structural and biological uses. Perhaps, these
properties could even be made dependent upon electrochemical
potential thereby creating new vistas for electronic materials,"
says chemist Mike Clarke, the NSF program officer who oversees
Wilker's award.

Source: Eurekalert & others

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